8 x 8 x 4 Inch PVC Sewer & Drain Wye Tee for SDR-35 S&D Pipe, Gasketed. A tee is a plumbing fitting that allows you to connect three sections of SDR-35 PVC tubing or Piping. Each of the three connections has gasketed connections, the two outside trunk connections measure 8 inch nominal size and the bottom outlet connection of the tee measures 4 inch nominal size. The fitting is specifically used in order to connect three sections of SDR-35 PVC pipe. These fittings are great for sewer and drain applications such stack vent (aka. stink stack, soil stack or stink pipe) and other drain applications within a residence or commercial property. However they should NEVER be used for gas or compressed air applications.